You don't want to use any petroleum based oils or solvents in a spring piston air gun because the force of the spring moving when firing can ignite the oil. What you want is a silicone based oil that is designed for spring piston air guns. Just Google Air Gun Chamber Lubricating Oil.
For the trigger issue Google GRT-III. This is a replacement trigger. This company makes several different ones designed to fit common designs of air guns.
